# SPDX-License-Identifier: Apache-2.0
# Copyright 2019 Western Digital Corporation or its affiliates.
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
# http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.



#Simple start up file for the reference design

#ifdef D_LLVM_COMRV
/* disable warning for reserved registers use - we are using comrv
   reserved register and don't want to see these warnings. */
.option nowarnreservedreg
#endif /* __clang__ */

  .section ".text.init"
  .global _start
  .type   _start, @function




_start:
  #clear minstret
  csrw minstret, zero
  csrw minstreth, zero

    #clear registers
    li  x1, 0
    li  x2, 0
    li  x3, 0
    li  x4, 0
    li  x5, 0
    li  x6, 0
    li  x7, 0
    li  x8, 0
    li  x9, 0
    li  x10,0
    li  x11,0
    li  x12,0
    li  x13,0
    li  x14,0
    li  x15,0
    li  x16,0
    li  x17,0
    li  x18,0
    li  x19,0
    li  x20,0
    li  x21,0
    li  x22,0
    li  x23,0
    li  x24,0
    li  x25,0
    li  x26,0
    li  x27,0
    li  x28,0
    li  x29,0
    li  x30,0
    li  x31,0


    #cache configuration
    li t1, 0x55555555
    csrw 0x7c0, t1
    fence.i
    # initialize global pointer
    .option push
    .option norelax
    la gp, __global_pointer$
    .option pop
    la sp, _sp

/* [OS] we dont have this memory to load from ----
    // Load data section
    la a0, _data_lma
    la a1, _data
    la a2, _edata


    bgeu a1, a2, 2f
1:
    lw t0, (a0)
    sw t0, (a1)
    addi a0, a0, 4
    addi a1, a1, 4
    bltu a1, a2, 1b
2:
*/
    /* Clear bss section */
    la a0, __bss_start
    la a1, _end
    bgeu a0, a1, 2f
1:
    sw zero, (a0)
    addi a0, a0, 4
    bltu a0, a1, 1b
2:

    /* Call global constructors *//*
    la a0, __libc_fini_array
    call atexit */
    call __libc_init_array

#    #hart id
#OS    csrr a0, mhartid
#OS    li   a1, 1
#OS 1:  bgeu a0, a1, 1b
    # argc = argv = 0 t0
    li a0, 0
    li a1, 0

    call main
    
    #[OS]: no need for exit, just endless loop here.....was: tail atexit
    # loop here
 2:  j 2b
